package cn.rkylin.apollo.common.util;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

/**
 * @Description: 以静态变量保存Spring ApplicationContext,
 *               可在任何代码任何地方任何时候中取出ApplicaitonContext
 * @author zhangXinyuan
 * @Date 2016-8-25 下午 20:26
 * @version 1.00
 */
public class BeanUtils implements ApplicationContextAware {
	private static ApplicationContext applicationContext;

	/**
	 * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量
	 */
	@Override
	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
		BeanUtils.applicationContext = applicationContext;

	}

	/**
	 * 取得存储在静态变量中的ApplicationContext
	 */
	public static ApplicationContext getApplicationContext() throws BeansException {
		checkApplicationContext();
		return applicationContext;

	}

	/**
	 * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型. 
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(String name) {
		checkApplicationContext();
		return (T) applicationContext.getBean(name);
	}

	/**
	 * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型. 
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(Class<T> clazz) {
		checkApplicationContext();
		return (T) applicationContext.getBeansOfType(clazz);
	}

	/**
	 * 清除applicationContext静态变量. 
	 */
	public static void cleanApplicationContext() {
		applicationContext = null;
	}

	private static void checkApplicationContext() {
		if (applicationContext == null) {
			throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");
		}
	}

}
